Nitrogen use in spring wheat impacted by crop diversification, management, and tillage
Dryland wheat production potential in the northern Great Plains (NGP) often is limited by N availability impacted by various management practices. A 4‐yr study was conducted in northeast Montana to relate spring wheat (Triticum aestivum L.) productivity and N utilization to management system (conventional and ecological), tillage (till and no‐till), and four crop rotations (continuous spring wheat, spring wheat‐pea [Pisum sativum L.], spring wheat‐hay barley [Hordeum vulgare L.]‐pea, and spring wheat‐hay barley‐corn [Zea mays L.]‐pea. Ecological management included greater seed rates, delayed planting dates, banded N fertilizer, and increased stubble height compared to conventional management with standard seed rates and planting dates, short stubble height, and broadcast N fertilizer. Continuous spring wheat showed the lowest grain yield, with the least efficient utilization of N compared to 2, 3, and 4‐yr rotations. Mineral nitrogen‐use efficiency (NUE) was 37% lower for continuous wheat than other rotations. Increasing complexity of crop rotation had little impact on wheat production or N relationships. The delayed planting date associated with ecological management of spring wheat contributed to 33% less efficient use of N compared to an early planting date with conventional management. Overall, results indicated that crop rotation and management system often impacted N relationships with wheat production, while tillage impacts differed with year. Differences in yield and N use of spring wheat varied among years, underscoring the need to refine management systems given the highly variable precipitation patterns typical of the NGP.
This is a manuscript of an article published as Allen, Brett, Andrew William Lenssen, Upendra M. Sainju, Jalal D. Jabro, and William Stevens. "Nitrogen use in spring wheat impacted by crop diversification, management, and tillage." Agronomy Journal (2021). doi:10.1002/agj2.20686.